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P0412 is a diagnostic trouble code (DTC) for "Secondary Air Injection System Switching Valve A Circuit Malfunction". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
Secondary Air Injection System Switching Valve A Circuit Malfunction
P0412 is an OBD-II generic code that the engine control module (ECM) got input from the air injection system driver that the air pump or air switching valve has malfunctioned with an open or short circuit.
The air injection switching valve voltage is too high indicating an open circuit.
The air injection switching valve voltage is too low indicating an short circuit.
The ECM sets the code from diagnostic inputs from the air injection system driver.
The Check Engine Light will be illuminated and the code is set in ECM memory and freeze frame.
The air injection system pump may not come on.
The engine may not have any drive symptoms except a check engine light is on.
Scans codes and documents the freeze frame data in order to verify the problem
Clears the engine codes retest the air injection system for proper operation
Tests the air injection switching valve is controlling the air injection pump operation during tests
Checks the resistance of the air injection pump and air injection switching valve
Checks the air injection pump for proper voltage between the pins of power and ground
Not checking for proper battery voltage above 8 volts to the air injection pump before replacing the pump for no air pumping out of it
Not checking the air injection pump power relay for burnt wire connections before replacing a bad air injection pump or air switching valve
The air injection pump system is to help lower the emissions coming out the exhaust and can cause the vehicle to fail emission testing.
The Check Engine Light being on causes the vehicle to fail emission testing.
The air injection pump should not cause any drive symptoms other than a Check Engine Light.
Code P0412 is a problem with the air injection system driver in the ECM cannot turn on the air pump to test it during startup. A shorted air injection pump circuit can short out the air injection driver in the ECM and should be considered when diagnosing the problem.
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